Bearing unit for windrowers

ABSTRACT

A bearing unit comprising a stationary radially outer ring with a spherical radially outer surface with a convex shape, a radially inner ring that is rotary about a central rotation axis (X) of the bearing unit and is mounted on a rotating or oscillating shaft. A diametrical through-hole is formed in a first cylindrical portion that is used to receive an elastic element for locking the radially inner ring on the shaft, a plurality of rolling bodies interposed between the radially outer ring and the radially inner ring to enable the relative rotation of the two rings, and a locking element locking the radially inner ring on the shaft. The radially inner ring is provided with two threaded through-holes from opposite sides with respect to the radially outer ring and to the rolling bodies, for housing respective grub screws for locking the radially inner ring on the shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority to Italian Patent Application No. 102021000012422 filed on May 14, 2021, under 35 U.S.C. § 119, the disclosure of which is incorporated by reference herein.

FIELD

The present disclosure relates to a bearing unit for windrowers provided with mechanical rakes coupled to a tractor. Said bearing unit is simple and cheap to produce, making it suitable for use in the manufacturing sector and in particular in the agricultural sector.

BACKGROUND

Bearing units may be provided with rolling elements and systems for clamping the unit to a rotary shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will now be described with reference to the appended drawings illustrating various non-limiting exemplary embodiments by way of example, in which:

FIG. 1 is a cross-section view of a bearing unit provided with a locking system using an elastic pin and grub screws, according to exemplary embodiments of the present disclosure,

FIG. 2 is an axonometric projection of the bearing unit in FIG. 1,

FIG. 3 is a cross-section view of the radially inner ring of the bearing unit in FIG. 1, and

FIG. 4 is a lateral view of the radially inner ring of the bearing unit in FIG. 1.

DETAILED DESCRIPTION

Bearing units are used to enable one component or unit to move relative to another component or unit. The bearing unit may have a first component, for example a radially inner ring, that is fastened to a first component, for example a rotary shaft, and a second component, for example a radially outer ring, that is fastened to a second component, for example a stationary housing. Typically, as in the aforementioned examples, the radially inner ring is rotary while the radially outer ring is stationary, but there are applications in which the outer element rotates and the inner element is stationary. In any case, the rotation of one ring in relation to the other inside the rolling bearing unit is enabled by a plurality of rolling elements that are positioned between the cylindrical surface of one component and the cylindrical surface of the second component, normally referred to as raceways. The rolling elements can be balls, cylindrical or conical rollers, needle rollers and similar rolling elements.

Various different systems for fastening the radially inner ring to the rotary shaft may be provided. The simplest method, which is in particular suitable for hollow shafts, requires the radially inner ring and the shaft to include axially matching through-holes, through which an elastic element (pin, gudgeon or the like) is inserted under pressure to rigidly connect the two components.

Other more complex and more costly methods for coupling the rotary shaft and the radially inner ring together may be provided. These include, in ascending order of complexity/expense: using a pair of clamping elements to lock the radially inner ring on the shaft (for example a pair of socket-head screws or grub screws that are inserted into dedicated threaded through-holes formed in an axially end portion of the radially inner ring to stably lock the radially inner ring to the shaft. The two socket-head screws and the related holes are normally arranged at an angular distance of between approximately or about 60° and approximately or about 120°); interference fitting the radially inner ring on the rotary shaft; and using clamping collars to deform the end portion of the radially inner ring, which is forced onto the rotary shaft.

Despite the simplicity, the solution using through-holes and elastic pins has some drawbacks. The most common drawback occurs where a user, such as a manufacturer of agricultural machinery, requires both a bearing unit that can be mounted using an elastic element, and a bearing unit that has to be mounted by tightening the pair of grub screws on the shaft. This is because, for a given use, the optimal positioning of the bearing unit does not always correspond to the position of an elastic-pin through-hole on a rotary shaft, or because such bearing units are designed for another type of application, such as machines with solid rotary shafts.

Regardless of the reason in relation to the intended use, this means that the user has to have different bearing units in stock and, given the number of bearing units to be mounted, results in an excessive number of article codes in stock, and a consequent increased risk of error in the mounting phase.

A bearing unit with a system for locking the radially inner ring on a rotary shaft that overcomes the described drawbacks is disclosed.

The present disclosure provides a bearing unit that is versatile in terms of locking the radially inner ring on a rotary shaft for different machine layouts. This is achieved in the bearing unit according to the present disclosure by coupling two locking systems together, one with an elastic element and one with grub screws.

In particular, the radially inner ring has two cylindrical portions of equal axial dimensions projecting outwards from the radially outer ring on opposite sides of the radially outer ring. A through-hole is formed in one cylindrical portion to receive an elastic element. Furthermore, according to the disclosure, a threaded through-hole is formed in each cylindrical portion to receive a grub screw, the axes of the two threaded holes being orthogonal and incident with respect to the rotation axis of the bearing unit.

Advantageously, the threaded hole formed in the cylindrical portion, provided with the through-hole for the elastic element, is positioned at a predetermined angle from the through-hole.

The present disclosure therefore provides a bearing unit including a radially inner ring provided both with a through-hole and a pair of threaded holes having the features set out in the attached claims.

One embodiment of a bearing unit 10 according to the present disclosure is described below purely by way of example and with reference to the aforementioned figures. The bearing unit 10 for use in the agricultural sector and/or manufacturing industry (for example the textile, mining, motor-vehicle or food industries) can be interposed for example between a rotary shaft and a housing element (not covered by the present disclosure).

With specific reference to FIG. 1, the bearing unit 10 is for example used in a windrower provided with mechanical rakes coupled to a tractor, and includes, a stationary radially outer ring having a spherical radially outer surface with a convex shape, a radially inner ring 33 that is rotary about a central rotation axis X of the bearing unit 10, mounted on a rotating or oscillating shaft (of a known type, and therefore not shown in the figure) of the rake; a plurality of rolling bodies 32 interposed between two rings to enable the relative rotation thereof; and a cage 34 for the rolling bodies to hold the rolling elements of the row of rolling bodies 32 in position.

Throughout the present description and the claims, terms and expressions indicating position and orientation, such as “radial” and “axial,” should be understood with reference to the central axis of rotation X of the bearing unit 30.

According to various embodiments, the bearing unit 10 is also provided with sealing means 35 to seal the bearing unit from the external environment. Hereinafter, the sealing means 35 can also be referred to more simply as seals 35, and shall be understood to refer to the same component.

The radially inner ring 33 is divided, with respect to an axis of symmetry Y of the plurality of rolling bodies 32, into two cylindrical portions 33 a, 33 b of equal axial dimensions A (see FIG. 3), projecting outwards from the radially outer ring 31 on opposite sides of said radially outer ring 31. A diametrical through-hole 36 is provided in a first cylindrical portion 33 a to receive an elastic element, which is of a known type and is therefore not shown in the figure. The elastic element is inserted into the diametrical through-hole 36 and through the oscillating shaft to lock the radially inner ring 33 onto said oscillating shaft.

Furthermore, according to the disclosure, a threaded through-hole 37, 38 is formed in each cylindrical portion 33 a, 33 b of the radially inner ring 33 to receive a grub screw 39 (see FIG. 2), the axes A₃₇, A₃₈ of the two threaded holes being orthogonal and incident with respect to the rotation axis of the bearing unit X. In other words, the two threaded holes 37, 38 are formed in the radially inner ring 33, from opposite sides with respect to the radially outer ring 31 and to the plurality of rolling bodies.

Advantageously, the axis A₃₇ of the threaded hole 37 formed in the cylindrical portion 33 a, including the diametrical through-hole 36 for the elastic element, is positioned at a predetermined angle α from the axis A₃₆ of the through-hole 36 (as shown in FIG. 4). The angle α is preferably between 30° and 60°.

According to the disclosure, the bearing unit has been developed to optimize production and stock, as well as to make the characteristics of two different machines interchangeable. The bearing unit provides for locking the radially inner ring in relation to the oscillating shaft, incorporating both the through-hole for the elastic element and a pair of threaded holes for the grub screws. As a result, a user mounting the bearing unit in a first type of machine can use the locking method with an elastic element or the locking method with a pair of grub screws, mounting the bearing unit in any position along the oscillating shaft, and not necessarily in line with the through-hole. Conversely, a user mounting the bearing unit on any other type of machine that does not include a rotary shaft with through holes can use the grub-screw clamping system. It is evident that both locking methods can be used simultaneously to guarantee an optimal axial hold, by increasing the force required to cause an axial movement of the bearing unit.

Various embodiments of the disclosure increase the axial length 2A of the radially inner ring 33. In the known layouts, the radially inner ring is asymmetrical in relation to the vertical axis Y of the bearing unit 10 (axis passing through the center of the rolling bodies 32 and of the raceways of the rings). Increasing the length of the ring and in particular making the ring symmetrical (in relation to the vertical axis Y of the bearing unit) improves the balance of the system; which includes two axially opposite threaded holes 37, 38 as shown in FIGS. 1 and 3. In various applications, the threaded holes both have the same axial coordinate (their centers are on the same circumference as the center of the bearing), but with an angle between them that may be between 60° and 120°. According to various embodiments, the bearing unit is better balanced, or does not excessively weaken the side where the diametrical through-hole 36 for the elastic element will also be present; in addition to not weakening the side provided with the through-hole for the elastic element, a threaded hole for each side allows for mounting with symmetrical clamping.

A bearing unit according to various embodiments provides versatility by providing two different locking systems, and can be applied to different machine layouts, and provides a greater axial hold compared to the known solutions by using both of the locking systems, an improved balance of the bearing unit by increasing the axial length and symmetry of the radially inner ring, and using a single catalogue product without the need for dedicated production processes other than the drilling and threading operation, wherein a single item for two different machines is easier for users to manage. The concept of management used above refers to stock, manufacturing and sales interfacing, machine implementation, operator training, etc.

In addition to the example embodiments described above, numerous other variants of the disclosure are possible according to a person of ordinary skill in the art. Such embodiments should be understood to be examples and do not limit the scope, applications or possible configurations of the disclosure. Indeed, although the description provided above enables the person skilled in the art to carry out the present disclosure at least according to one example configuration thereof, numerous variations of the components described could be used without thereby moving outside the scope of the disclosure, as defined in the attached claims interpreted literally and/or according to the legal equivalents of same. 

We claim:
 1. A bearing unit, comprising: a radially outer ring comprising a spherical radially outer surface with a convex shape, wherein the radially outer ring is stationary; a radially inner ring, rotatable around a central rotation axis (X) of the bearing unit, wherein the radially outer ring is configured to be mounted on a rotating or oscillating shaft, in which a diametrical through hole is made on a first cylindrical portion of the radially inner ring, the diametrical through hole being configured for housing an elastic element locking the radially inner ring on the rotating or oscillating shaft; a plurality of rolling bodies interposed between the radially outer ring and the radially inner ring configured to allow the relative rotation of the radially outer ring and the radially inner ring; and at least one locking element configured to lock the radially inner ring on the rotating or oscillating shaft, the at least one locking element comprising: two threaded through holes formed in the radially inner ring, from opposite sides with respect to the radially outer ring and with respect to the plurality of rolling bodies, wherein the two threaded through holes are configured for housing respective grub screws locking the radially inner ring on the rotating or oscillating shaft.
 2. The bearing unit of claim 1, wherein the radially inner ring is divided, with respect to an axis of symmetry (Y) of the plurality of rolling bodies, into two cylindrical portions of equal axial dimensions (A) projecting outwards from the radially outer ring on opposite sides of the radially outer ring itself and in which each cylindrical portion is provided with one of the threaded through holes, wherein one of the two cylindrical portions comprises the first cylindrical portion of the radially inner ring.
 3. The bearing unit of claim 1, wherein first and second axes (A₃₇, A₃₈) of the two threaded through holes are orthogonal and incident with respect to the central rotation axis of the bearing unit (X).
 4. The bearing unit of claim 2, wherein first and second axes (A₃₇, A₃₈) of the two threaded through holes are orthogonal and incident with respect to the central rotation axis of the bearing unit (X).
 5. The bearing unit of claim 1, wherein a first axis (A₃₇) of the threaded through hole formed in the first cylindrical portion provided with the diametrical throughhole, is angularly distant from an axis (A₃₆) of the diametrical through hole according to an angle (α) ranging between about 30° and 60°.
 6. The bearing unit of claim 2, wherein a first axis (A₃₇) of the threaded through hole formed in the first cylindrical portion provided with the diametrical through hole, is angularly distant from an axis (A₃₆) of the diametrical through hole according to an angle (α) ranging between about 30° and 60°.
 7. The bearing unit of claim 3, wherein the first axis (A₃₇) of the threaded through hole formed in the first cylindrical portion provided with the diametrical through hole, is angularly distant from an axis (A₃₆) of the diametrical through hole according to an angle (α) ranging between about 30° and 60°.
 8. The bearing unit of claim 4, wherein the first axis (A₃₇) of the threaded through hole formed in the first cylindrical portion provided with the diametrical through hole, is angularly distant from an axis (A₃₆) of the diametrical through hole according to an angle (α) ranging between about 30° and 60°.
 9. The bearing unit of claim 1, wherein the at least one locking element of the radially inner ring on the shaft comprises an elastic element housed in the diametrical through hole.
 10. The bearing unit of claim 1, wherein the at least one locking element of the radially inner ring on the shaft comprises a pair of grub screws housed, one each, in the two threaded through holes.
 11. The bearing unit of claim 10, wherein the at least one locking element of the radially internal ring on the shaft further comprises an elastic element housed in the diametrical through hole. 